Human Immunodeficiency Virus (HIV) is presumably the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). Many attempts have been and continue to be made to find mechanisms and agents to prevent or to cure an HIV infection, without much success.
Attention has been focused in part on measures that prevent infection by the virus. One method aimed at the heterosexual population has been the vaginal application of agents prior to and during intercourse, which agents are intended to inactivate the virus or remove its infectivity. An example is the use of surfactant- or detergent-based spermicides, exemplified by nonoxynol-9 ("N-9"), which have demonstrated activity against HIV and other sexually-transmitted diseases (STDs) at concentrations that would be expected to exist during intercourse after pre-coital application of the spermicide to the vagina. However, it is not necessarily a requirement that there be simultaneous presence of anti-STD and spermicidal activity. Currently available formulations of N-9 include jellies and sponges for spermicidal use in the vagina. However, at concentrations which may be effective in reducing the rate of gonococcal and chlamydial cervical infections, the rate of symptomatic irritation of the vagina and/or penis is substantially increased. In a study on the efficacy of the N-9 contraceptive sponge in preventing sexual acquisition of HIV by highly exposed women, N-9 was not effective in reducing infection by HIV, but genital ulcers and vulvitis occurred with substantially increased frequency.
It therefore is of interest to use delivery systems for anti-STDs that maintain contact between the anti-STD and the infective agent without harming host or partner tissue.
Relevant Literature
N-9 has been shown to be effective at inhibiting several sexually transmitted diseases, including AIDS, gonorrhea, chlamydia and trichomonal infections, syphilis and genital herpes. See, e.g., Niruthisard, S., et al., Lancet, 339: 1371 (1992).
Vaginal application of a commercially available contraceptive jelly containing 5% N-9 has been shown to be effective in preventing vaginal transmission of herpes simplex virus type 2 (HSV-2) infections in mice. Whaley, K. J., et al., J. Infect. Diseases, 168:1009, 1010-11 (1993). Dextrans and the carageen types of polysaccharides have been shown to have an anti-HIV potential. See, e.g., Pearce-Pratt, R. et al., Bio. Reprod., 48:431,432 (1993).
The efficacy of a formulation based on a cross-linked polycarboxylic acid polymer for moisturization of skin or mucous membranes, such as vaginal tissue, is described in Robinson, J. R., European Patent Applications Serial Nos. 90300327.5 and 90300340.8.